I actually got this idea from my LYS that was selling "The Yarn Bra" that does the same thing. But I have many packages of hoseiry that I have never used. And you can purchase them for cheaper and get more out of them.
The first picture is a really small ball of spun silk yarn as you can see with my hand for scale.
This royal blue one is a skien I recently spun up. It is worsted wieght (11 WPI) and it works with it. This one has the closed foot.
And this sky blue ball is a 7oz skien rolled into a ball on the ball winder. The bottom is open, but it wraps around it so it's cool.
And the bonus of using hosiery? Keeps the yarn protected and CLEAN! Not to metion it keeps the yarn orderly when the ball or skien gets down to those last few yards.
Until next time...